Traffic is a nightmare, with portions of the 710 and 405 freeways inundated by several feet of water and the Grapevine and Cajon Pass closed by snow. Evacuations are ordered for more than 1,000 homes.

The third day of an intense series of winter storms brought widespread flooding, huge waves and more evacuations throughout Southern California, with another powerful front expected to hit this morning.

Wednesday's storm lacked the dramatic tornado conditions of Tuesday's, but it dropped significantly more rain.

Streets from San Pedro to Sunland flooded. And the afternoon commute turned into a nightmare when portions of the 405 and 710 freeways were inundated by several feet of water, stranding several cars. The Grapevine was closed for much of the day because of snow, and officials Wednesday night shut down Interstate 15 at the Cajon Pass. A rock slide closed California 1 at Mugu Rock in Ventura County.

There were reports of hail and scattered power outages. At least one waterspout off the coast of Hermosa Beach prompted city officials to call residents, telling them to stay indoors. And a dozen children were rescued in separate swift-water rescues in La Habra and Yorba Linda.

Lightning struck two Southwest Airlines Boeing 737s before they landed safely at Bob Hope Airport in Burbank. The airliners, which were flying from Oakland and Sacramento, landed at 9:38 a.m. and 9:57 a.m., respectively. Both were taken out of service to check for possible damage.

The back-to-back-to-back wallops have dropped more than 3 inches of rain on downtown Los Angeles and more than 5 inches in Long Beach since Sunday. The precipitation has pushed L.A. into an above-average rainfall total for this time of year -- with a total of 8.23 inches since July.

Those numbers are sure to rise when the new storm hits the region around midmorning today. Forecasters said the storm will bring sustained rainfall for about six hours before tapering off late today. Another less powerful storm will arrive Friday.

"Keep your eyes peeled for tornadoes and some lightning and thunder," said Bill Patzert, a climatologist for the Jet Propulsion Laboratory in La Cañada Flintridge. "But as this moves into my area up here in the foothills, sooner or later, something here has to break loose."

The biggest concern remains the Station fire-ravaged foothill areas of La Cañada Flintridge, La Crescenta, Glendale, Tujunga and Acton, where more than 1,000 homes were under mandatory evacuation.

Many homeowners refused the order and remained in their residences, frustrating officials.

Los Angeles Mayor Antonio Villaraigosa and Police Chief Charlie Beck issued stern warnings that lives could be at risk and pleaded with residents in mudslide-prone areas to evacuate. The city, Villaraigosa said, could be looking at a "La Conchita situation" if the intense rains continue as forecast. In 2005, 20 people were killed when the hillside above the small Ventura County community collapsed.

"This weather event is not over," Beck said.

Debris flow experts from the U.S. Geological Survey offered their own cautionary notes, likening the heavy rains to a 1969 storm that triggered landslides, mudslides and floods that killed 34 people near Glendora. Rivers of mud, rocks and debris can cascade down mountainsides and through channels, picking up sediment along the way at speeds up to 35 mph, experts said.

By 5 p.m. Wednesday, rainfall was abating and the storm water rushing down Ocean View Boulevard in La Cañada Flintridge was mostly clear -- a good sign for residents who had ignored repeated evacuation orders.

Like many other holdouts, George Wiktor, 60, spent the day keeping a close eye on neighbors' homes and studying the latest National Weather Service forecast.

But he was anxious about today.

"The National Weather Service says [Thursday] is the big one," he said. Chuckling, he added, "In fact, the meteorologist who authored the very latest forecast was even somewhat excited about tomorrow's storm. He called it 'the most interesting storm in 20 years.' "

Outside, dump trucks rumbled to and from a nearby debris catch basin filled to the brim with mud, rocks and trees.

"We're hoping for the best, but preparing for the worst," Wiktor said. "For me, that means spending another day at home being vigilant."

In the same neighborhood, Rick and Starr Frazier felt equally secure in their decision to stay. Around their home on Ocean View Boulevard, they had erected concrete and water-filled barriers and filled at least 200 sandbags.

The only opening is at the driveway. "If anything comes down, we feel protected," said Starr Frazier, 45, who works for the La Cañada Chamber of Commerce.

"We really fortified ourselves and I don't think we're going to have a problem," said Rick Frazier, 52, a TV editor. "The worst that can happen is that we'll be blocked in until Monday."

On Wednesday afternoon, the South Bay took the brunt of the storm for the second straight day. Torrential rains led to a collapsed roof in Paramount, flooded the 710 Freeway again and forced Cal State Long Beach to cancel classes until Friday.